Advertisers have been selling us back our childhood memories since the 1950s — and it is as powerful a strategy as ever. In a 2013 study, NBCUniversal Integrated Media noticed that brands that connected to the past shot to the top of its Brand Power Index.

Brands are finding it effective to add a mix of retro-cool to their advertising campaigns, but the Twinkies comeback may be the first time that an iconic product has resurrected a faltering brand.

Enriched wheat flour, modified cornstarch, high fructose corn syrup — Twinkies have survived a whole foods revolution and a diet food craze (though at 120 calories a cake, you could certainly do worse).

When James Dewar introduced his Twinkie in 1931, he was simply looking for a use for pound cake that would appeal to shoppers long after berries were out of season. The two-for-a-nickel treats — initially injected with a banana filling — were an instant hit. Dewar himself admitted to eating three Twinkies a day for 50 years; he lived to be 88.

After a long tenure in American supermarkets and convenience stores, Hostess, the brand behind Twinkies, announced it was declaring bankruptcy in 2012. Some analysts criticized the company for failing to respond to Americans' changing palates.

Perhaps it's the nostalgia. From comic books to the silver screen, state fairs to science projects, legal legends to urban legends, artifacts to art exhibits, Howdy Doody to Archie Bunker — Twinkies have been baked into our national pop culture for generations.

After the announcement, Hostess was able to use an outpouring of public nostalgia to persuade an investment company, Metropoulous & Co., to fork over a check for $410 million.

The rescued company will relaunch the Twinkie on July 15 and restock supermarket shelves with creme-stuffed cakes made from the same recipe that consumers remember from their tin lunchboxes.

Shake It Like A Polaroid Picture

When Edwin H. Land introduced instant photography to consumers in 1949, it sparked a one-day sellout of every Polaroid camera leaving the production line.

It was more than two decades before Polaroid released its magnum opus, the foldable compact SLR SX-70. The release was huge news and was followed by the more affordable Swinger in 1965 and the popular OneStep in 1978.

By 2008, digital cameras had pushed Polaroid films into the past. Polaroid stopped making its signature film and declared bankruptcy — for the second time since 2001.

But aficionados were not ready to let it go. A group of Polaroid purists in Denmark, who go by the moniker The Impossible Project, bought a Polaroid factory and are making film that fans say keeps getting better and better.

The group has a new invention that will be hitting store shelves in August: The Instant Lab — a smartphone-to-instant-photo printing device. Starting with a Kickstarter goal of $250,000 to fund the project, the group ended up raising twice that. The device helps turn pictures from your smartphone into actual, physical instant photos. After a picture is loaded to the companion app, you place your phone face down onto the top of the device. The app then exposes the instant film with the photo you're "printing."

For its part, Polaroid did regroup — the company is solvent again. In 2009, it introduced a camera with an old-style look and a twist: The digital camera has a built-in instant printer.

New Old Music

During the CD age, vinyl was considered a relic of an earlier time in music. Many record labels closed their pressing plants, and the market largely ignored those music fans still clutching their LPs: college radio stations and electronic dance music DJs who argued that the discs' grooves produced a warmth and depth unmatched by digital codes.

Now there is a rebirth of new record collectors — many of whom were born after the introduction of the Sony Discman. Musicians are insisting that their music be released on all formats: MP3s, CDs and LPs. Every major label releases vinyl records, and there has been an increase in new pressing plants around the country.

There have also been recent vinyl reissues of a growing number of classic albums — the complete Beatles collection, early Rolling Stones and Bob Dylan, to name a few. The comeback is big enough that indie star Carrie Brownstein (of Portlandia fame) jokingly played a vinyl enthusiast in an American Express commercial.

Why Retro Is Trendy

But for all its marketability, there is no consensus on why retro is cool.

It could be that we're just running out of new things to flaunt — maybe our trendsetters are lazy. In fashion, cutting-edge clothes are much more risky than vintage looks; retro has already been tried and tested (perhaps that's why Banana Republic keeps adding throwback collections).

More likely, we like retro things because we are holding on to a romanticized vision of an earlier time. It's like playing dress-up — "new" old technologies help us pretend that everything about that earlier era was simple and good.

It's easy to be cynical of the time we live in, when we can so easily whitewash the struggles of decades past.